Scientists converge on East Coast erosion zone

The Waipaoa River catchment and ocean basin are continuing to fascinate international scientists. Twenty United States scientists are the latest arrivals to collaborate with New Zealand researchers, this time examining distinctive sediment layers that hold clues to global climate change.

The Waipaoa study area covers about 3100km2, including the city of Gisborne. Its unique physical and historic features make it one of the world's greatest sites for studying climate change.

Landcare Research and NIWA are co-convening the visit by scientists from the MARGINS Source-to-Sink programme, which is funded by the US National Science Foundation. The multi-million dollar programme focuses on how sediment on land and on the ocean floor records the effects of climate change, earthquakes, volcanic eruptions and deforestation. The scientists are here for a week-long workshop that will form the basis of ongoing research collaboration with New Zealand scientists.

Landcare Research programme leader Dr Noel Trustrum says the Waipaoa site is a unique natural laboratory. "More than 90% of the sediment washed down from the hills by the Waipaoa River is trapped in a bathtub-like basin offshore, so it is easy to study. The layers of sediment act as a tape recorder of the earth's history. They contain signals that tell scientists of the relative effects of floods, cyclones, earthquakes and volcanic eruptions over thousands of years. They also show the effect of climate change, and the impact of deforestation on the area's severe erosion problems. A lot has happened in the Waipaoa area * and it's all recorded in that silt and sediment on the ocean floor and on the riverbed.

"Through studying the Waipaoa area, researchers are building an understanding of how both natural events and human-induced changes affect the coastal margins where most of the world's population is concentrated."

NIWA programme leader Dr Lionel Carter says in the past, geomorphologists collected data only from sediment on the land, while oceanographers collected data only from the sea. "However, by bringing together the expertise of both NIWA and Landcare Research, we have been able to understand the intimate links between the land and the ocean. We can now evaluate, for instance, how changes in the sea temperature affect weather patterns on shore. Analysis of past storm events preserved in lake and ocean deposits allow improved prediction of storms in a future that is dominated by marked climate change. This knowledge will enable towns and cities to better cope with the continuing unsettled weather predicted for the next century.

"Combining our skills with those of the US researchers will extend our capabilities still further. Access to state-of-the-art technology and new computer models will substantially enhance the timeliness and usefulness of the research results.

"This will benefit New Zealand's local bodies and government, and will aid world climate change knowledge as a whole."

The visiting scientists will be spending time at various Waipaoa sites today and tomorrow, before a series of talks and lectures in Palmerston North and Wellington from Wednesday to Friday. The visit is the second major overseas delegation to the East Coast in three months. In February, researchers from four countries headed to the Waipaoa River as part of a collaborative project on river sediment and flood management.

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